KCSAN: data-race in __fput / __tty

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision
4c18f12c	assessment-security	DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌	❓	KCSAN: data-race in __fput / __tty_hangup (4)	2026/05/21 17:52	2026/05/21 17:52	2026/05/21 18:33	d5742584
2e237de2	repro		❓	KCSAN: data-race in __fput / __tty_hangup (4)	2026/03/10 13:50	2026/03/12 13:47	2026/03/12 15:19	86914af9
36f7465e	assessment-kcsan	Benign: ✅ Confident: ✅	❓	KCSAN: data-race in __fput / __tty_hangup (4)	2026/01/14 20:15	2026/01/14 20:15	2026/01/14 20:38	a9d6a792

Title	Replies (including bot)	Last reply
[PATCH] hfs: Validate CNIDs in hfs_read_inode	30 (30)	2026/01/06 10:21
[PATCH] tty: tty_io: fix race between tty_fops and hung_up_tty_fops	3 (3)	2024/07/22 16:10
[fs] Are you OK with updating "struct file"->f_op value dynamically?	1 (1)	2024/05/12 13:45
[PATCH] tty: tty_io: remove hung_up_tty_fops	44 (44)	2024/05/04 22:17
[syzbot] [kernel?] KCSAN: data-race in __fput / __tty_hangup (4)	14 (15)	2023/04/25 22:09

Title

Replies (including bot)

Last reply

[PATCH] hfs: Validate CNIDs in hfs_read_inode

30 (30)

2026/01/06 10:21

[PATCH] tty: tty_io: fix race between tty_fops and hung_up_tty_fops

3 (3)

2024/07/22 16:10

[fs] Are you OK with updating "struct file"->f_op value dynamically?

1 (1)

2024/05/12 13:45

[PATCH] tty: tty_io: remove hung_up_tty_fops

44 (44)

2024/05/04 22:17

[syzbot] [kernel?] KCSAN: data-race in __fput / __tty_hangup (4)

14 (15)

2023/04/25 22:09

Kernel	Title	Rank 🛈	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __fput / __tty_hangup (3) serial	6	2	1466d	1484d	0/29	auto-closed as invalid on 2022/08/23 04:41
upstream	KCSAN: data-race in __fput / __tty_hangup (2) serial	6	1	1522d	1522d	0/29	auto-closed as invalid on 2022/06/29 01:31
upstream	KCSAN: data-race in __fput / __tty_hangup serial	6	1	2188d	2188d	0/29	auto-closed as invalid on 2020/08/31 10:07

Rank 🛈

upstream

KCSAN: data-race in __fput / __tty_hangup (3) serial

1466d

1484d

0/29

auto-closed as invalid on 2022/08/23 04:41

upstream

KCSAN: data-race in __fput / __tty_hangup (2) serial

1522d

0/29

auto-closed as invalid on 2022/06/29 01:31

upstream

KCSAN: data-race in __fput / __tty_hangup serial

2188d

0/29

auto-closed as invalid on 2020/08/31 10:07

================================================================== BUG: KCSAN: data-race in __fput / __tty_hangup write to 0xffff88811df03b48 of 8 bytes by task 9274 on cpu 0: __tty_hangup+0x1c1/0x510 drivers/tty/tty_io.c:612 tty_vhangup+0x17/0x20 drivers/tty/tty_io.c:691 pty_close+0x266/0x290 drivers/tty/pty.c:77 tty_release+0x1e7/0xaf0 drivers/tty/tty_io.c:1745 __fput+0x29e/0x630 fs/file_table.c:512 ____fput+0x1c/0x30 fs/file_table.c:540 task_work_run+0x130/0x1a0 kernel/task_work.c:233 get_signal+0xdc1/0xf10 kernel/signal.c:2818 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x15d/0x8c0 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x23c/0x3c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff88811df03b48 of 8 bytes by task 9278 on cpu 1: __fput+0x599/0x630 fs/file_table.c:508 ____fput+0x1c/0x30 fs/file_table.c:540 task_work_run+0x130/0x1a0 kernel/task_work.c:233 get_signal+0xdc1/0xf10 kernel/signal.c:2818 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x15d/0x8c0 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x23c/0x3c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0xffffffff85aadd80 -> 0xffffffff85aadc70 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 9278 Comm: syz.4.1530 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026 ==================================================================

Crashes (9):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Assets (help?)	Manager	Title
2026/07/21 05:40	upstream	b95f03f04d47	de6a700d	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __fput / __tty_hangup
2025/09/15 19:40	upstream	f83ec76bf285	e2beed91	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __fput / __tty_hangup
2025/01/05 02:23	upstream	ab75170520d4	f3558dbf	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __fput / __tty_hangup
2024/10/04 01:16	upstream	7ec462100ef9	d7906eff	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __fput / __tty_hangup
2024/08/09 16:39	upstream	ee9a43b7cfe2	a83d9288	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __fput / __tty_hangup
2024/06/15 14:19	upstream	44ef20baed8e	f429ab00	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __fput / __tty_hangup
2024/02/29 15:32	upstream	805d849d7c3c	352ab904	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __fput / __tty_hangup
2023/08/07 04:39	upstream	f0ab9f34e59e	4ffcc9ef	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __fput / __tty_hangup
2023/03/29 08:37	upstream	fcd476ea6a88	fc067f05	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __fput / __tty_hangup

Crashes (9):

Assets (help?)